It started with a letter that Martha Burk figured would never see the light of day.

When she mentioned the all-male membership at Augusta National, the National Council of Women's Organization didn't even vote on whether to take action.

"It was a very casual conversation at the end of a board meeting," Burk said in a recent interview. "I had found out about this club and said I was thinking about writing a letter. Everyone said, 'Fine, write the letter.' I never expected my letter to go anywhere. I thought in a few years I might have followed up with a phone call."

There was no need.

Hootie Johnson, the chairman of Augusta National, wrote a three-sentence reply to her that club matters were private. The next day he issued a scathing, 932-word statement to the media that defended the rights of a private club and said a woman joining Augusta National would be on the club's timetable and "not at the point of a bayonet."

So began the biggest controversy in Masters history.

It culminated 20 years ago with a rally during the third round. Burk, wearing a bulletproof vest under a green golf shirt, spoke to about 40 supporters in a lot a half-mile away from Magnolia Lane because authorities denied her permission to protest across from the club.

And then it all went away, or so it seemed. Television sponsors returned in 2005, after the Masters had cut them loose to keep them out of the fray. It wasn't until nine years after the protest that Augusta National announced former Secretary of State Condoleezza Rice and South Carolina financier Darla Moore had accepted invitations to join.

"We did not succeed in our goal to get the club open to women at the time," Burk said. "They waited a long enough time that we wouldn't get credit. But had we not done that, I think there still would not be women members."

During the course of this battle, Burk was invited to be part of a Golf World magazine cover. The headline was "Year of the Women." She was among five women on the cover as the top newsmakers of the year, and had no way of knowing then that one of them — Suzy Whaley — would go on to become the first female president at the PGA of America.

The landscape has changed over the last 20 years, but not quickly enough for some who still see a great gender disparity. Augusta National has at least six female members wearing green jackets during the Masters.

The most noticeable — and more relevant — change is outside the club.

Two years after Augusta National had its first female members, Whaley in 2014 was elected secretary of the PGA of America, a 28,000-strong organization of club professionals. She rose to president four years later. Diana Murphy in 2016 became only the second president in the 121-year history of the U.S. Golf Association.

The Royal & Ancient Golf Club voted overwhelmingly in 2014 to accept women for the first time, and later removed Muirfield from the British Open rotation when the historic golf club in Scotland rejected mixed membership.

Muirfield held a second vote in 2017 and changed with the times. The club known as the "Honorable Company of Edinburgh Golfers" that dates to 1744 not only has female members, it hosted the Women's British Open last year for the first time.

The USGA announced in 2007 the U.S. Women's Open would be going to Pebble Beach, the most iconic venue of the men's U.S. Open. That becomes reality this summer. Also on the USGA calendar is a second staging the U.S. Open and the U.S. Open Women's Open at Pinehurst No. 2 in consecutive weeks.

"If you look at the world, if you look at golf, we've come a long way," Whaley said. "I like to paraphrase Condi Rice. She always talks about suffrage and things that happened before. But also look forward. What can I do to make it better for those who come behind us?"

Whaley earned her place on that Golf World cover as a high-energy Connecticut club pro who became the first woman since 1945 to qualify for a PGA Tour event. Annika Sorenstam, who also was on the cover, played a men's event two months ahead of Whaley thanks to a sponsor invitation.

Whaley now serves on the board of the Annika Foundation, and they recently caught up while doing a CBS special. Whaley recalls the Masters controversy being "right on top of us" as they prepared to play against the men. They rarely made it through an interview without being asked about it.

"We were all thrown together in this women's movement in golf," Whaley said.

Whaley played the LPGA Tour briefly, married club pro Bill Whaley, had two daughters and never lost the itch for golf. She spent hours observing famed instructors, and it led to her getting certified as a teaching pro by the LPGA Tour and the PGA of America.

After moving to Connecticut, she was recruited to run a public course called Blue Fox Run. The owner, Lisa Wilson Foley, wanted a woman as the head pro. Whaley learned on the job.

She has seen women in roles not many were in 20 years ago — engineers behind the technology of drivers, rules officials, the general manager of a 140-year-old club that hosted the U.S. Open last year, the president of a club is hosting the 2028 Olympics in Los Angeles, the C-suite in major golf organizations.

"We can celebrate the progress, where we are today," she said. "My question is where are we going next? What's next for corporate? What's next for media? The bottom line is this — I'm really happy with where we're headed. We need serious support to get where we should be."

Alex Baldwin is the first woman to be president of Korn Ferry Tour, the primary path to the PGA Tour, and her role is expanding to bring more tours into the pathway.

"We had a dinner in Savannah (Georgia), and we had 60 different title sponsors. We had event operators come out, we had a golf course owner. It was people who represented our tour," Baldwin said. "It literally was 50-50 representation men and women. I've been to a lot of dinners where I'm the only woman. It was a cool moment to have."

The Korn Ferry Tour is where careers began for the likes of Scottie Scheffler and Justin Thomas, Bubba Watson and Zach Johnson.

Baldwin, in her fourth year as president, has noticed fewer questions about being a woman in this leadership role, and she's happy about that. She would attribute the gains more to a changing culture in society, not just golf.

Even so, there are moments that remind her of change. One happened in Chile last week, where the Korn Ferry Tour played for the first time.

"A young woman sought me out — she was involved in a junior program," Baldwin said. "She said, 'I wanted to meet you. You're a woman, and I can't tell you how inspiring that is.'"

Burk never paid much attention to golf before she wrote that letter to Augusta National, and now she only is aware of the sport when the Masters rolls around.

At 81, her time is spent largely on equal pay and other political issues affecting women. She also hosts three-minute podcasts called, "Equal Time with Martha Burk."

Burk, with her Texas twang, never needed a lot of time to get to her point.

"How many women are at Augusta now? Six? That's 2%," she said, basing it on the assumption the club has about 300 members. "Let's do a little math.

Women are still pathetically behind in U.S. business, anyway. We've just broken though to 10% (of CEOs) in Fortune 500s. If you equate that — which we ought to — to the membership at Augusta National, they ought have to have 30."

One of her kids recently gave her a program called "Storyworth" to share memories. One prompt asked her to tell the craziest thing that ever happened to her.

The answer came easily.

She wrote a letter to an all-male club, not fully knowing about Augusta National or the Masters. She recalled her oldest son telling her, "Mother, you have attacked the Westminster Abbey of golf."

"Even though it has been 20 years, people still stop me on the street or remark when they hear my name," Burk concluded in her Storybook entry. "I'm fond of saying the Augusta fight will be on my gravestone."